Hot-dip metallic materials, including hot-dip Zn metallic materials and hot-dip Al—Zn metallic materials, are coated with a layer of metal protective coating on the surface to form a protective film, so as to prevent corrosion. Therefore, the properties of the metal protective coating are very important for corrosion protection of hot-dip metallic materials.
For example, the Chinese Patent Application No. CN101608306A discloses a passivating liquid, which also belongs to a metal protective coating, wherein, the passivating agent is a water solution that contains water soluble molybdenum compound, boric acid, water soluble organic substance, and silicasol, and the water soluble organic substance is a mixture of alcohol and organic carboxylic acid.
However, experiments have shown that the corrosion resistance, water resistance, thermal resistance, and fingerprint resistance of the protective film formed by the metal protective coating are still not good enough.